1. Technical Field
The present invention relates to a network formation display apparatus and a signal path establishment apparatus suitably used for transmission and reception of Musical Instrument Digital Interface (MIDI) signals or audio signals between a plurality of networked nodes.
2. Related Art
Conventionally, the applicants propose the music LAN (mLAN, registered trademark) that constructs a local area network (LAN) comprising nodes such as a personal computer, an electronic musical instrument, a mixer, an effector, and a recorder, and freely sends and receives MIDI signals and audio signals between the nodes. The music LAN is disclosed in Japanese Non-examined Patent Publication No. 2001-203732. The music LAN complies with the IEEE1394 standard. Normally, each node is provided with two IEEE1394 ports. The IEEE1394 ports of each node are connected in a daisy chain configuration to build up a hardware connection of the music LAN.
In this specification, a term “LAN connector” is used to represent a hardware terminal used for connection between nodes and the like. A term “terminal” is used to represent a logical unit to input or output MIDI signals and audio signals. Logically “connecting” the terminals with each other enables transmission and reception of MIDI signals and audio signals between the logically connected nodes. When a MIDI signal is to be transmitted from a node A to another node B, for example, a logical connection must be established between one of MIDI output terminals of node A and one of MIDI input terminals of node B.
The technology disclosed in Japanese Non-examined Patent Publication No. 2001-203732 displays a list of terminals on a personal computer screen to present connection relationship between the terminals and to edit the connection relationship as needed. According to the technology, a user can select either “MIDI signal” or “audio signal” as the list to be displayed. The selected list is displayed in a table format comprising left and right columns. The left column lists output terminal names. The right column lists input terminal names. When a connection state is established between any of output and input terminals, these terminal names are displayed on the same row. To change the connection state, the user can move any input terminal name on the right column to the right of an intended terminal in the output terminal column based on the “drag-and-drop” manner using a mouse tool. In this manner, the output terminal and the input terminal are connected. The user can specify either of the “MIDI signal” list and “audio signal” list independently of each other.
Since the above-mentioned technology displays the connection relationship between terminals in a table format on character notation basis. Accordingly, users feel it difficult to intuitively and fast understand the connection relationship. Users also feel it cumbersome to change the connection relationship between the terminals.
In the above-mentioned technology, the user can select one of the “MIDI signals” list and the “audio signals” list. The user may change the order of nodes or terminals listed in the selected list. Then, the user may switch the display to the other of the “MIDI signals” list and the “audio signals” list. However, the other list does not reflect the change made to the previously selected list. Thus, when displaying the other list, the user cannot promptly recognize the display contents.